1. Field of the Invention
This invention is related to an improved structure of a scanner and in particular one which is compact in size and easy to assemble.
2. Description of the Prior Art
It has been long desired to have a scanner which is compact in size and easy to assemble, but none of the scanners on the market are satisfactory in these areas. Referring to FIG. 1, the conventional scanner 1 generally includes a glass window 11 and a carriage 12. The carriage 12 includes a casing 121, a light source 122, a first mirror 123, a second mirror 124, a first mirror 123, a second mirror 124, a third mirror 125, a fourth mirror 126, a lens assembly 127, and a charge coupled device (CCD) 128. The casing 121 is formed with an opening 1211 and a piece of paper 13 is placed face down against the glass window 11 above the carriage 12.
As shown, the casing 121 is generally rectangular in shape, in which are arranged the light source 122, the mirrors 123-126, the lens assembly 127 and the charge coupled device 128. As the carriage 12 is moved beneath the page 13, the light source 122 illuminates the paper 13 and the carriage 12 captures light bounced off individual areas of the paper 13. Thereafter, the light from the paper 13 is reflected through the mirrors 123-126 to the lens assembly 127 which focuses the light onto the charge coupled device (CCD) 128 that translate the amount of light into an electrical current.
However, as shown in FIG. 1, the casing 121 is a closed rectangular member with only one opening 1211 at the top and so all component parts must be correctly arranged inside the casing 121 before it is closed. As a consequence, when required to adjust the component parts, it is necessary to open the casing 121 thereby causing much inconvenience in maintainence. In addition, since the mirrors 123-126 are mounted inside the casing 121, there must be fastening means for fixing the mirrors in place thus increasing the manufacturing cost.
Therefore, it is an object of the present invention to provide an improved structure of a scanner which can obviate and mitigate the above-mentioned drawbacks.